Mechanism of action of the sulfonylureas is

Ans. is 'a' i.e., K ATP channel blocker * Sulfonylurease provoke a brisk release of insulin from pancreas. They act on the so called "Sulfonylurea receptors" (SUR1) on pancreatic b-cell membrane - cause depolarization by reducing conductance of ATP sensitive K+ channels. This enhances influx of Ca+2 - degranulation. They do not cause hypoglycemia in pancreatectomized animals and type 1 diabetes (Presence of at least 30% of functional b-cells in essential for their action). A minor action reducing glucagon secretion by increasing insulin and somatostatin release has been demonstrated.